Air conditioning apparatus



Oct. 1, 1940. l w EWALD 2,216,551

AIR CONDITIONING APPARATUS Filed July 23, 1938 2 Sheets-Sheet 1 Oct. ll,1940.

W. EWALD AIR CONDITIONING APPARATUS Filed July 23, 1958 2 Sheets-Sheet 2INVENTOR www .BY M444@ ATTORNEY Patented Qct. 1, 1940 AUNITED dSTATESPATENT OFFICE Am. coNnrrloNmG APPARATUS Warren Ewald, La Crosse, Wis.Appucatimruiy 2a, 193s, serial No. 220,926-` 3 Claims.

One of the objects of my invention is to provide a unit ventilator whichwill produce a method of heating an enclosure whereby at apre-determined temperature a pre-determined amount of cold air will beadmitted, whereby at a predetermined'higher temperature the dampercontrolling the flow of air through the radiator will close and thedamper controlling the ow of air through the bypass will open, andwhereby when l0 the 'damper controlling the. ow of air through theradiator is closedthat the steam`valve will then close, and whereby at ahigher pre-determined temperature an additional definite amount ofoutsideair will be introduced and the recirculated air cut oi.

Another object of my invention is an apparatus which will accomplish theabove sequence with a minimum of working parts.

Another object of my invention is to provide a mechanism which willoperate according to the above sequence.

The foregoing and many other. specific features of my invention are setforth in the follow ing specification, where I describe what I considerthe preferred embodiments of my invention. These are illustrated in theaccompmying drawings where- Figure 1 represents a cross-sectional view.of

'the unit ventilator.

.Figure 2 shows a cross-sectional viewl of the bellows 60 and associatedmechanism.

Referring to Figures 1 and 2, the umt ventilator has side walls I0 and Itop wall I2,v bottom VWan I3, and an outlet I4 with a fresh air inlet I6and a. recirculated air inlet |5. Air is drawnY through theradiator' I8and thebypas 9. by

means of the fan I1. A metal bellows 20 is actuated by 'air pressure inthe pipe 6|, responsive to the temperature of the room 8. The upperportion of .the bellows is free to move and-is iredly fastened at 2|. toresist the movement of the bellows. A valve stem 23 is -secured to thetop wall 24 of the bellows 2|).- A yoke 25 in the stem 23 is of sulcientlength so that the movement of, the'valve stem 23 will actuate the lever3| but have no eect upon the steam passing through the valve until afterthe lever-3| has completed its`full movement. A valve 26 controls the owof steam to the radiator I8 by means of s valve throttle 21 and a-va1veseat 28.

Figure 29 represents a steam inlet tothe valve 26 and ligure 30represents a 'valve bonnet through which the lstem 23- moves. The lever3| passes through the yoke 25 and is .actuated up- 22 represents aspring tending (Cla 236-38) wards by the bottom of the yoke 25 so thatthe movement 'upward of the stem 23 will raise the damper and open theradiator passage. Withea downward movement of the stem 23 the damperwill lower due to gravity and completely close the radiator passagebefore the valve throttle 21 closes sulliciently to shut off the steam,at which time the upper portion of the yoke 25 will be in contact withthe lever 3|. To insure closureof the radiator passage, a spring 40 maybe aillxed to the top of the lever 3| so that the top of the yoke 25will press upon the spring, complete the movement of the damper and thenclose the valve. l

The lever 3| is pivotally secured at 32 and is connected by the link 33with the arcuate damper 31,)the black lines showing the damper closingthe bypass and opening the passage through the radiator, while .thedotted lines show the position of the damper when the lever 3l.lsdepressed, opening the bypassqand closing the radiator passage. widththan the radiator passage, the damper because of its arcuateform is ableduring its entire movement to fullyfclose either of said passage-waysand also to partially close either .of

y said passage-ways. Thus, with a downward movement of the lever 3|, theradiator passage is "closed, the bypass is open, and with 'an upwardmovement of the lever 3| the movement of the damper 31 is reversed. Themovement of the lever 3| occurs only when the vthrottle 21 is completelyoff its seat so that the steam supply is not throttled or closed duringthe movement of the damper 31. VThe steam supply is not affected untilthe damper 31 'is entirely closed.' Upon this happening, the movement ofthe valve stem 23 will operate to close the valve andentirly shut offthesteam.v

Thus. by action of the single. motor bellows the air going through theradiator is rregulated and the air going through the bypass isreglgated,

While the bypassopening is of smallerand whenthis has been accomplishedthe steam is shut oi. It is also obvious that on the reverse cycle thesteam valve will be entirely open kbefore the damper 31 will startto"\operate. The

'regulation of the ingress of indoor and outdoor air is regulated by amechanism contained in thev bottom of the unit'. The recirculated airinlet I5 is controlled by a damper 48 pivotally. secured at to theoperating arm 59 of 'the pneumatic bellows operator 60. Likewise, thefree end of rod 54 terminates in a pin 1| riding in slot 58 of the samemovable plate 51. Tension spring 8| con-A nects rod 50 and rod 54tending to pull both dampers toward one another, which tendency islimited by the pins 10 and 1| at certain times in contact with the endsof the slots 53 and 58, and" at other times by the dampers contactingimmovable stops at their extreme open positions.

The plate 51 moves horizontally -andwhen at the extreme end of itsstroke toward fresh air opening I6, the end of the slot 58 forces pin 1Iin this same direction and through rod 54 moves damper 55 to a positionfully closing fresh air inlet I6. Upon -movement of plate 51 away frominlet I6, the pin 1I is held in contact with this same end of slot 58 bytension ofv spring 8|, and the damper is thereby caused to assume apartly open position (position18), and upon -further movement of plate51 a fully open position (position 19).' During the aforesaid movementof plate 51, spring 8| tends to hold damper 48 immovably at its extremeopen position, and slot 53 permits plate 51 to move by pin 10 withoutcausing movement of said pin 10. Upon further movement of plate 51 awayfrom inlet I6,

'damper 55 remainsstationary at position 19 withv f inlet I5. Upon areversal of direction of plate 51, the cycle of damper movement willlikewise be reversed. It is to be understood from the above that thesedampers are caused. to move in sequence and never simultaneously.

Bellows 60, which operates by the same method as the bellows 20, isactuated by the air supply in the common supply pipe 6 I which isresponsive to the room thermostat 62. The spring 13 in the bellows 60 isof pre-determined. strength so that the bellows will operate at adifferent air pressure than the bellows 2|). The movement of the bellows.60 will actuate the stem 82 secured to the bellows at 15 and will movethe arm 16, which rocks on the pivot 11, thus causing the movement ofthe plate 51. For example, when the temperature of the room is. 68 orbelow, there will be 0# of pressure inthe line 6I and all of thecontrols will be in the position as shown in black on Figure 1. From 68to 69- the thermostat will build up a pressure in the liner6l from 0 to341?,

which will be sufiicient to move the bellowsGIl and open the fresh airdamper predetermined minimum, as shown by the dotted line 18. From 69 to701/2" the thermostat will build up a pressre in' the line 6I of 3 to8'#, during' which the damper,31 completely closes the radiator passageand Will 'completely open the bypass 8. At 8# pressure the valvethrottle 21 will completely seat. When the temperature around thethermostat rises from '10i/2 to 71, the pressure will increase in thepipe 6I from 8 to l0#, which ill cause the bellows. 6I) to furtheroperate and by moving the plate 51 cause the damper 55 to fur' ther opento fresh air to the position shown by' the dotted line 18. When thetemperature sur- .rounding the thermostat increases from '71 to 'Z13/2,the pressure will be built up in the pipe 6| from l0 to 13#, which will4cause the bellows 60 to move further and by moving the plate 51 closethe recirculated damper 48 to the position shown by the dotted line 80..

Referring to Figure 2, this represents a means of operating the freshair intake damper and the recirculating air .intake damper in accordancewith' the cycle previously described. Rod 50 operates the recirculatingair damper throughat- .tached shaft. Rod 54 operates the fresh airdamper. Plate or arm 59, which is attached to plate 51, is immovablysecured to the arm 16, pivoted at 11, operated by piston 82. Thepiston82 is secured to the inner movable surface of bellows 6I). When theinterior of bellows 60 is subjected to varying amounts of air pressurethrough tube 6| from the room thermostat, bellows 50 will expand movingpiston 82 against the resistance, first, of compression spring 13 andfinally against the combined resistance of spring 13 plus spring 83.Spring 13 is a-comparatively light spring having `an initialcompression, such that the bellows and piston will start to move atapproximately l# air pressure Within the bellows. During l# and 3# airpressure, the bellows and piston will move to a position where contactwith sleeve 84 interrupts this motion. y

During this movement the fresh air damper will open to thepre-determined position to admit the minimum desired quantity of freshair. During this movement also, due to the slot in plate 51, therecirculated air damper does not move.

Compression spring 83 has an initial compresision, such that itwill holdthe bellows and piston immovably between air. pressures' 3# to 9#. Afterthe airpressure within the bellows 80 has attained 9#, the bellows andpiston again start to move against the combined resistance of spring 13and 83 and will move to their extreme position at approximately 13# airpressure. During this movement .the fresh air damper will beprogressively opened to its extreme position, and in subsequent orderthe recirculation air damper will be progressively closed. -It is.. tobe understood that the air pressure in 60 varies in accordance with thetemperature of the room surrounding the thermostat which supplies andcontrols the air pressure to the bellows GII.` Normally f thistemperature and, therefore, the air pressure willflnd some vintermediatevalue forany given set of conditions and the dampers will consequentlybeforced to assume a resulting interme. diate stationary position l Tofurther explain the manner in which the .two intake dempers functionmechanically with slotted plate 51, it should be understood thatvinitially during the heating up period in the morning that the freshair damper will be in the completelyclosed position and vthe.recirculating d damperin a completely open position. At this th'eextreme position in its guiding slot of plate 51 away from the fresh airdamper and is held inv this position by the pull of tension spring 8|.At this same stage, the terminal pin or link 18 is in the extremeposition in itsguiding slot of plate 51, also away fromthe freshairdamper. The tension spring 8| would tend to move pin10 -within theslot of plate 51 but suchmovement is prevented by a mechanical 'stop atthe extreme position which the recirculating intake damper can assume.`

When the plate -51 moves in a direction away from the fresh air damperto the aforementioned minimum fresh air position, linkl 54 and the fresh`air intake vdamper likewise will move pulled by tension spring 8| andwith the terminal pin of link 54 at the original position relative toplate 51. During this movement the recirculating air damper and pin 10will remain stationaryA with the terminal pin 10 moving in the slot ofplate 51.

When the plate 51 again resumes movement in accor'dance with the higherair pressure in the bellows, then the fresh air damper and link 54 movein accordance therewith until the damper contacts a mechanical stop atits extreme open position. When this occurs and upon further movement ofplate 51, the terminal pin of link 54 commences to move within the slotof plate 51 against the tension of spring 8l. At this position where thefresh air damper has attained its extreme open position, the terminalpin 10 reaches the end of its slot in plate 51. Pin .10 is then forcedto move toward the recirculating air damper, moving this recirculatedair damper thereafter in direct accord with themovement of plate 51against the tension of spring 8|. At the extreme position of plate 51the recirculating air damper will be entirely closed. While I havedescribed the foregoing preferred embodiments of my invention, Icontemplate that many changes may be made without departing from thescope or spirit of my invention.

I claim:

1. In an' apparatus for conditioning the air in a room, the combinationof a casing with'a fresh air inlet, a recirculated air inlet, an airoutlet, a radiator, a fan moving air from said inlets to the outletthrough said radiator, dampers `for controlling said fresh air andrecirculated air inlets,

means interconnecting said dampers for their sequential operation, anair actuated motor operating through said damper operating means at apre-determined room temperature toopen the fresh airinlet apre-determined amount and at a pre-determined higher temperature to openthe fresh air inlet a further pre-determined amount, and at a furtherpre-determined higher temperature to close the recirculated air inlet.

2. In an apparatus for conditioning the air in a room, acasing havingfresh air and recirculated `air inlets and an air outlet, a radiator somounted within the casingas to provide a by-pass passage communicatingwith the outlet, a room thermostat, an air motor responsive to saidthermostat, a damper connected to said air motor to control the ow ofair through said radiator and t by-pass, a valve to control saidradiator, and actuating means for closing said valve when said damperisin position to cut ofi' the flow of air through said radiator andopening it when said damper closes the 'Dy-pass, a second air motorunder iniiuence of said thermostat, a pair of dampers controlling saidfresh air and recirculated air inlets, respectively, linkageinterconnecting said pair of dampers and second air motor to permit oftheir sequential operation in opening the air passages, said air motorsbeing also adjusted for sequential operation under the inuence of saidthermostat, whereby as the temperature rises above a predetermined pointthe radiator heat output is progressively decreased until entirely cutoff by closing of said valve and opening of the by-pass, following whichthe fresh air inlet is progressively opened and, in sequence, therecirculated air inlet is closed.

1 3. In an apparatus for conditioning' the air in a room, a casinghaving a" radiator so mounted within it as to provide a by-pass passagetherearound, a damper movable to control the ilow of air through saidradiator and by-pass. a valve through which heat exchange medium issupplied to said radiator, a thermostatically responsive motor connectedto said damper and valve, acting un'der the influence of roomtemperature to close said valve when said damper is in position to cut oflow o air through said radiator, a pair of dampers for controllingfresh air and recirculate'd air inlets, respectively, in said casing,linkage connecting said dampers for sequential operation, a secondthermostatically responsive motor also under the influence oi' roomtemperature operating said pair of dampers through said linkage.whereupon as the temperature rises from a pre'- determined minimum theflow of air through the radiator is reduced and the by-pass opens, thevalve supplying heat to the radiator is then shut oil?, more outside'air is next admitted by operation of the damper controlling the freshair inlet,

vand finally the damper controlling the recirculated air inlet isclosed, and upon a drop in room temperature the sequence of operationsis reversed.

WARREN EWALD.

